The present invention relates generally to sharing data across one or more data storage access nodes on a data storage network, and more particularly to systems and method for providing directory-based cache coherency across a distributed network of data storage access nodes.
In current storage networks, and in particular storage networks including geographically remote access nodes and storage resources, preserving or reducing bandwidth between resources and access nodes is highly desirable. It is therefore also desirable that data access be localized, in part to improve access speed to pages requested by host devices. Caching pages at access nodes provides localization, however, the cached data must be kept coherent with respect to modifications at other access nodes that may be caching the same data. Current storage network access solutions, however, do not provide viable coherency mechanisms for caching pages locally at storage network access nodes.
Accordingly, it is desirable to provide efficient data localization and cache coherency systems and methods that overcome the above and other problems. Such systems and methods should also provide reduced bandwidth usage, or messaging requirements, between storage network access nodes.